I know this is for 5.4 timing but I'm wondering if any of you who have done the whole timing thing have ever run into this problem. I did everything on mine and it runs perfect-- carrying 70 psi oil pressure on the highway and 25 at an idle. Very quiet till it warms up and then I get a loud squeal. I took the belt off and the squeal is still there. I've replaced everything up front before taking the belt off and no change. The only thing left on the front is the balancer but I can't see that squealing or could it? Also when I shut it off it seems to wind down. It's done this for about 5000 miles now and I've put a total of around 8000 since I did the timing. I've scratched all the hair off my head at this point. Anyone got any ideas? Thanks

 

perhaps the "squeal" is the oil pressure bypass. 70 lbs is excessive.

 

I've got a Melling 640HV with an 80 psi cutoff and wish I had gone with the 340 due to high pressure when I start it in really cold weather. The odd thing is that it only starts squealing after it is warmed up. When I start it on really cold mornings my pressure wil run up to 90 with no problem so I have to let it warm up before driving.

 

The bypass theory is an interesting one but it doesn't make sense that it starts bypassing when the oil is warmed up. The pressure drops when it's warm.

 

Degrease the belt/pulleys.
*EDIT, you said you tried it with the belt off, only one belt on this engine? nothing else external moving without the belt?

 

5.4 has only 1 belt.

 

This is interesting. I installed the M340 during my timing refit and an external Glowshift gauge. Using 5W-30 oil, I also get about 70 psi and 25 idle. With as much damage my engine took, I didn't think it would get 50 psi let alone 70. I also didn't think the M340 is capable of 70 psi?

I'm not sure if it's a wonky gauge or what. If it wasn't such a b@sttard to swap them out, I'd try a different gauge. I've used Glowshift before with no problems. At this point it doesn't really matter. I'm just glad it's not the factory 20psi or whatever Ford said was adequate.. lol. She runs great other than an annoying miss that only seems to happen in the mornings. It was suggested cleaning the throttle body and a new gasket might cure it, so we'll see.

With everything disconnected on yours and you still get the squeal... Hmmm. So what else is 'spinning' ? Is the noise crank or cam speed? I was thinking the tone ring on the crank was in backwards and might be hitting something, but I'd think your engine wouldn't run at all if that was the case.

Another thought: Do you have one of those front seal repair sleeves on your crank? If you do, I'm wondering if that might be it? Maybe it wasn't put in right and it's scraping on something, or perhaps it's slipping - I have no idea (I've never used one). I thought about putting one on mine, but I didn't like the way it installed and decided to leave it alone for now. I don't like the small groove worn in my balancer, but I can always swap it out later if it developed a bad enough leak.

Upload a video and sound of that squeal. Maybe it will help to identify it? Crank or cam speed is sticking in my head.... it's the only 2 things left to move other than hydraulics (oil/fuel).

~You have now entered the Triton Twilight Zone~

 

Thanks to everyone trying to help me. We went over that thing today with a stethoscope top and bottom and everywhere between. The sound was pretty loud between the engine and transmission. But you could hear it really good at the passenger side valve cover too. The man helping me took the oil fill cap off to see how loud it was inside and the squeal went away. Put the cap on and it squealed. I have a lot of vacuum inside making me think I might have a couple of hoses hooked up wrong. The squeal is a gasket or seal leaking air into the engine. Now just to find what I did wrong. Runs great except for that really annoying noise. Thanks everyone

 

I'm assuming you checked your PCV system is hooked up correctly? and the valve is working? potentially you have the PCV system hooked up backwards.

 

Kind of thinking that way. There has to be somewhere that isn't hooked right because I keep getting the faulty gas cap code too.